??????????ù??????????????????????????????

????????????????′??????????ζ???????????????????ù??????????????????Щ????????????з????
$ nslookup web1
;; connection timed out; no servers could be reached

????????????????￡????????????/etc/resolv.conf???????????????????????????????????????????????????κ????????IP??????????????????????????????????????????????????????????????????????ping?????????????????????????????????飺
search example.net
nameserver 10.1.1.3

??????????ping????????????????IP?????????????????????????￡????????У?10.1.1.3??????????????￡???????????????????????????????????????ping??????????????IP?????????????????????????￡???????????"????·?????????????"??????????????????????IP????????????????????С???????ping?????????????????????????????"???????????”????

???????????·???????????????????

??????????nslookup???????????????????′????????
$ nslookup web1
Server: 10.1.1.3
Address: 10.1.1.3#53
** server can't find web1: NXDOMAIN

???????????????????????????????????????????????????????????????web1?????????ζ?????????????????????????web1?????????????DNS????·?????С?????????????????λ??/etc/resolv.conf??????С????????????????????????????nslookup????????????????????????????web1.example.net????????????????????????????????????????????????????/etc/resolv.conf?н?????????????????·?????У????????????????????

???????????????????????Ч?????????????????????????????????????????ЩDNS????????????????????????????????м????????????????y??м?顣???????????????????????????????????????????Щ?????????????????????????????????????????????????г???????????????????????????????????????????????????

????????·?????????????

???????????DNS????????web1??????????IP 10.1.2.5???????????????????·????????????????????????????????ICMP???????????????ping web1??????????????ping????????????????????·????????????????????????????"??????????"??????????ping?web1?????????????е??????????????????ping????????????????????????ping??κ???????????????????????·?ɡ????·?????????????????traceroute???????????????????·??????????????????????????????????????????????????dev1??web1??????γ??·???????????????????
$ traceroute 10.1.2.5
traceroute to 10.1.2.5 (10.1.2.5)?? 30 hops max?? 40 byte packets
1 10.1.1.1 (10.1.1.1) 5.432 ms 5.206 ms 5.472 ms
2 web1 (10.1.2.5) 8.039 ms 8.348 ms 8.643 ms

??????????????????????dev1???????????10.1.1.1??????????????web1????????????λ????????????????????10.1.1.1????????????????????д??????·??????????????????????????????????????????????ping?web1??????????????????????
$ traceroute 10.1.2.5
traceroute to 10.1.2.5 (10.1.2.5)?? 30 hops max?? 40 byte packets
1 10.1.1.1 (10.1.1.1) 5.432 ms 5.206 ms 5.472 ms
2 * * *
3 * * *

????????????????????п???????????????????????檔????????·??????????????????????????????????·???????????????????????????????

$ traceroute 10.1.2.5
traceroute to 10.1.2.5 (10.1.2.5)?? 30 hops max?? 40 byte packets
1 10.1.1.1 (10.1.1.1) 5.432 ms 5.206 ms 5.472 ms
1 10.1.1.1 (10.1.1.1) 3006.477 ms !H 3006.779 ms !H 3007.072 ms

??????????????￡????????ping?????????????????????????????????????????????????????????????з?????м??????????????д????????μ??????豸?????web1??????ping???????????

?????????????????????????????ICMP??????????????????а?????·????鶴??????????????tcptraceroute?????(sudo apt-get install tcptraceroute)????????????·?????????Ω???????????tcptraceroute??????traceroute??